1. The Field of the Invention
The present invention relates to mobile communications technology, and more specifically, to mechanisms for enforcing a time-to-disconnect when sending messages to a wireless device that has a transient network address.
2. Background and Related Art
Computing technology has revolutionized the way people work and play and has contributed enormously to the advancement of humankind. Computers now aid in innumerable applications such as word processing, computer simulations, advanced gaming, voice recognition, among many more. Computing systems now come in a wide-variety of forms including, for example, desktop computers, laptop computers, Personal Digital Assistants (PDAs), and even mobile telephones and devices.
Some mobile wireless devices such as Personal Digital Assistants and wireless telephones have sophisticated memory and general processing capability that allow the mobile device to perform many tasks previously only performed by larger desktop computers. These tasks may even include tasks that require communication over data networks thereby allowing users to access the Internet and perform e-mail tasks even while they are mobile.
Generally speaking, there are two major transport level protocols that are used with the IP protocol. One is called Transmission Control Protocol (TCP). IP protocol deals only with the delivery of packets, whereas TCP enables two computing systems to establish a connection and reliably exchange data. TCP guarantees that the data will be delivered in the same order in which it was sent. The other major transport level protocol is User Datagram Protocol (UDP), which does not establish a connection between a sending and receiving computing system. Also, UDP provides very little error control. Since UDP does not involve an established connection between the two communicating computing systems, UDP is often referred to as a “connectionless protocol”. Other connectionless protocols include, for example, Ethernet and IPX.
Regardless of the particular protocol used, a mobile wireless device may often need to have its address changed. For example, when communicating over an IP-based wireless carrier network, a wireless device may disconnect from the wireless network thereby forcing a disassociation of the IP address that identified the wireless device while connected. Furthermore, even while connected to the carrier network, the wireless device may move from one Public Switched Data Network (PSDN) to another thereby forcing a reassignment of the IP address associated with the wireless device.
Accordingly, if the wireless device were to send a message over the wireless carrier network to the receiving computing system, there is some possibility that by the time a response to the message is returned, the assignment of the network address to the wireless device may have been revoked thereby resulting in non-delivery of the response. Worse yet, the old network address may have been assigned to another wireless device resulting in the wrong wireless device being delivered the response.
Accordingly, what would be desirable are mechanisms for more reliably communicating in a wireless environment in which network addresses are only transiently assigned to wireless devices.